1. Field of the Invention
The present invention is directed to a multiple ignition source exothermic reaction mold device and method of use. In particular, the present invention is directed to an exothermic reaction mold device wherein alternate sources of ignition may be chosen and utilized.
2. Prior Art
The use of exothermic reaction welding is well known for joining connectors, such as stranded metal cable, to each other and also for joining ground rods and other metal parts.
A mold, which may be composed of graphite, ceramic or other refractory material, contains an internal crucible in which a powder material is placed. The bottom of the internal crucible forms a seat for a metal retainer disc which supports the exothermic powder material prior to ignition. When the exothermic powder material is ignited, an exothermic reaction results in the crucible. The powder liquefies and the molten material melts the small metal disc at the bottom of the crucible, thus permitting the molten metal to flow through a tap hole or passageway into a weld cavity. The mold itself is often used multiple times and is transported from location to location.
The exothermic reaction process is initiated and the welding is initiated by an ignition which may occur from various sources. A spark or ignition gun, sometimes referred to as a flint gun, is often used to start the exothermic reaction which takes place extremely quickly once ignited. One example of a mold ignited by a spark gun is shown in Assignee's U.S. Pat. No. 6,776,386. Alternatively, an electric ignition element having high resistance is used to start the exothermic weld reaction. The electrical ignition system is advantageous since it may be initiated from a greater distance away from the mold itself.
Examples of prior molds that incorporate electrical ignition include Brosnan et al. (U.S. Pat. No. 4,889,324) which discloses exothermic welding with an ignition system 64 having a pair of leads 66 to connect to an ignition fuser or hot wire. The ignition device 70 is placed a depth of ⅛ inch in the reaction material and comprises a core of aluminum wire having an outer alloy coating. Column 6, lines 62-65, indicates that “an example of an ignition fuse 70 suitable for use with the present invention is a wire sold under the trademark PYROFUZE by Pyrofuse Corp., an affiliate of Sigmund Cohn Corp. of Mount Vernon, N.Y.”
Moore et al. (U.S. Pat. No. 5,145,106) discloses an ignitor with two lead wires with a high resistance bridge wire therebetween. The ignitor may be positioned above the material within the crucible of the mold. The shower of sparks or high temperature metal droplets are released from multiple points of ignition.
Walker et al. (U.S. Pat. Nos. 6,553,911 and 6,703,578) discloses an ignitor comprising two strips of metal foil separated by a layer of insulation. The ignitor includes one or more distortions in the form of punched holes. The voltage spike to the strips creates a spark plasma.
Kovarik et al. (U.S. Pat. No. 4,879,452) discloses an electrical ignition system for exothermic welding including an insulated wire pair 44 projecting into the exothermic material to be embedded therein.
Amos et al. (U.S. Pat. No. 4,885,452) discloses an exothermic reaction by creating a predetermined spark gap. In one embodiment, an insulated wire with a bare tip is placed below a surface of the reaction mixture. In another embodiment, spark gap may be established in a cartridge in a sidewall of the mold. In a further embodiment, the ignition may be sprayed on the top surface of the reaction mixture.
Gaman et al. (U.S. Pat. No. 6,316,125) discloses in FIG. 2 an electrical ignitor which projects through a wall of the crucible. The ignitor is positioned near the top of the charge.
Since the exothermic reaction weld is oftentimes made in the field in all types of conditions, it is desirable to have a choice of sources. Additionally, the weld may be made in confined spaces, such as a trench, wherein the ground rod is being installed or wherein a cable is being joined.
If the electrical ignition tools are not present at the site, it would be desirable to have an alternate source to ignite the exothermic weld reaction. Alternatively, if the spark ignition materials are not available, it would be desirable to have an alternate source to initiate the exothermic reaction welding.
Accordingly, it is a principal object and purpose of the present invention to provide an alternate source exothermic reaction mold device.
It is also a principal object and purpose of the present invention to provide a method or process wherein the exothermic weld reaction may be performed in alternate procedures.
It is also an object and purpose of the present invention to provide a multiple injection source exothermic reaction mold device wherein the ignition system is at all times visible and accessible in each source.
It is a further object and purpose of the present invention to provide a multiple injection source exothermic reaction mold device wherein the alternate starting elements are a part of a lid for the mold device.